Enable plugin writers to install packages on the host OS

[noissue]

README.md

@@ -105,6 +105,9 @@ The following settings are stored in `template_config.yml`.
 
   docs_test             Include a CI build for testing the 'make html' command for sphinx docs.
 
+  os_required_packages  A list of packages to be installed on the host OS (Ubuntu) in the build
+                        step.
+
   parallel_test_workers Run tests in parallel using `pytest-xdist` with N parallel runners. This
                         settings specifies N. By default it is 8.
 

plugin-template

@@ -46,6 +46,7 @@ DEFAULT_SETTINGS = {
     "latest_release_branch": None,
     "lint_requirements": True,
     "noissue_marker": "[noissue]",
+    "os_required_packages": [],
     "parallel_test_workers": 8,
     "plugin_app_label": None,
     "plugin_default_branch": "main",

templates/github/.github/workflows/build.yml.j2

@@ -23,6 +23,11 @@ jobs:
       {{ checkout(repository="pulp/pulp-openapi-generator", path="pulp-openapi-generator") | indent(6) }}
       {{ setup_python() | indent(6) }}
       {{ install_python_deps(["packaging", "twine", "wheel", "mkdocs", "jq"]) | indent(6) }}
+      {%- if os_required_packages %}
+      - name: "Install OS packages"
+        run: |
+          sudo apt-get install -y {{ os_required_packages|join(' ') }}
+      {%- endif %}
       - name: "Build package"
         run: |
           python3 setup.py sdist bdist_wheel --python-tag py3